GHSA-68jx-f42c-7599: CSRF
Problem The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Admin Tool applications from the site's main entry script instead of the dedicated typo3/ directory.
Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints.
Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session.
Solution Update to TYPO3 versions 13.4.34 LTS, 14.3.6 LTS that fix the problem described.
Credits Thanks to Hổ Cao Từ for reporting this issue, and to TYPO3 core & security team member Benjamin Franzke for fixing it.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
composer/typo3/cms-coreto a version that resolves this vulnerability.Fixed in 14.3.6 - Upgrade
Upgrade
composer/typo3/cms-backendto a version that resolves this vulnerability.Fixed in 13.4.34 - Upgrade
Upgrade
TYPO3to a version that resolves this vulnerability.Fixed in 13.4.34 - Upgrade
Upgrade
TYPO3to a version that resolves this vulnerability.Fixed in 14.3.6
Event History
Frequently Asked Questions
Who can exploit this issue in practice?
An attacker needs the ability to execute JavaScript on any domain belonging to the same TYPO3 instance, such as through a cross-site scripting vulnerability on a frontend page. Exploitation also requires an authenticated victim with a backend or Install Tool session to visit or interact with the attacker-controlled script.
What requests are improperly accepted?
Backend routes and Install Tool endpoints may accept Fetch/XHR requests originating from scripts on the instance's own domains, including frontend pages. The requests execute with the authenticated victim's user-session privileges.
Which TYPO3 versions contain the fix?
The issue is fixed in TYPO3 13.4.34 LTS and 14.3.6 LTS. Update the TYPO3 core and backend components to the applicable fixed release.